The invention relates to a method for the preparation of a paper reel for flying reel change according to the precharacterizing clause of claim 1 and an apparatus for carrying out the method according to the precharacterizing clause of claim 7. Such methods and apparatuses are used in reel cellars of printing works.
It is known that paper reels can be prepared for flying reel change by using an adhesive tape which joins the edge of the web end to the next inner layer and at the same time has, on the outer surface of the paper reel, an adhesive surface, for adhesive bonding to the residual reel, cf. for example DE-A-43 39 309. Recently, such adhesive tapes have also become available (cf. for example so-called Flying Splice System 551 from ASS-Etikett GmbH, Flying Splice Print Line tesa 51100 from Tesa AG or DE-A-196 32 689), which consist of an outer tape and an inner tape which are arranged one on top of the other and are connected in a separable manner. The inner tape is provided with an inner adhesive surface for joining to the next inner layer whereas the outer tape has an outer adhesive surface for joining to the web end and the residual roll.
For mounting conventional tapes, methods have been proposed in which a web section is unwound from the paper reel, the adhesive tape is mounted on the edge of the web end on the outside of the paper web and the latter is then rolled up again and the edge of the web end is joined to the next lower layer by means of projecting adhesive labels simultaneously mounted there, and corresponding apparatuses (cf. DE-C-195 40 689). However, they cannot be directly adopted since the adhesive tape is mounted there on the outside of the paper web, which is not possible in the case of adhesive tapes of the novel type. This also applies to similar cases where the joining of the edge of the web end to the next lower layer is performed by means of a separate so-called butterfly, while, for producing the joint with the paper web of the residual reel, a double-sided adhesive tape is mounted on the outside of the paper web, just before the edge of the web end (DE-C-39 18 552).
DE-A-38 34 334 discloses a method of the generic type and a corresponding apparatus, which is suitable for the use of adhesive tapes of the novel type described above. After a web section has been unwound so that a part thereof hangs over an oblique support surface mounted below the reel, an edge of the web end is produced by cutting off an end section along a cutting line running over the support surface, and the adhesive tape is then pressed there onto the inside of the outermost layer and the web is rolled up again. In this procedure, the position of the unrolled web section is not constantly under control, so that slight lateral shifts or waves form and may interfere with the procedure and cause web winding errors. Moreover, the paper reel must be rotated, i.e. must be rotatably mounted, which considerably increases the complexity of the apparatus.
A method which is similar in the basic principles and the corresponding apparatus, which are described in EP-A-1 041 025, ensure the control of the unrolled web section by a procedure in which the inside thereof is first held in an adhesion area by means of suction orifices and the end section is cut off for the preparation of the edge of the web end and then the outside is held by a second adhesion area while the adhesive tape is pressed onto the inside along the edge of the web end. However, this requires a considerably complicated design, especially since here too the reel has to be rotatably mounted.
It is the object of the invention to provide a method in which the position of the paper web is always under control. Moreover, it should be capable of being carried out with little effort. This object is achieved by the features in the characterizing clause of claim 1. The invention provides a method in which the unrolled web section, which is subsequently placed again on the reel, never hangs freely but is always under tension. Thus, the position of the replaced web section is exactly defined and free of errors. In addition, rotation of the reel is not required. It therefore need not be clamped.
It is a further object of the invention to provide a suitable apparatus for carrying out the method according to the invention. This object is achieved by the features in the characterizing clause of claim 7. The apparatus according to the invention enables the method to be carried out reliably and cleanly. It can moreover be produced relatively simply and with moderate effort.